Type 1 diabetes is a disease characterized by lack of insulin due to autoimmune destruction of pancreatic beta-cells. Although insulin injections supply the amount of hormone necessary for survival, they often fail to provide tight regulation of blood glucose levels resulting in long-term complications such as neuropathy and cardiovascular disease. Here we propose to use gene therapy as an alternative therapeutic modality to supply constant baseline levels of insulin and regulate insulin secretion according to demand. Specifically, we propose to develop tissue engineered skin made of genetically modified keratinocytes as an in vivo delivery device to secrete insulin for the treatment of diabetes. We will construct retroviral vectors that regulate insulin secretion through exogenous administration of small organic molecules. Using optimal gene transfer protocols, we will transduce epidermal keratinocytes and examine secretion of active insulin from cells in culture and from stratified epidermal tissues. Transplantation of genetically modified skin equivalents onto athymic diabetic mice will be used to examine the effects of keratinocyte insulin secretion on blood glucose levels and determine the efficacy of insulin regulation in response to exogenous agents. Tissue engineered skin will be genetically modified to provide baseline amounts of insulin between meals and higher amounts before meals to mimic the insulin secretory response of beta-cells to nutrient stimulation. Our ultimate goal is to create a cell-based device to provide better control of blood glucose levels and overcome the devastating long-term effects of diabetes. Our team is composed of a tissue engineer (STA), a molecular biologist (KLK) and a diabetes expert (SGL). This combination of expertise is essential for the success of this multifaceted project, which involves molecular biology, tissue engineering, tissue transplantation and controlled drug delivery to engineer a cell-based device for regulated delivery of recombinant insulin.